/keys for empty keys return string instead of json

[faboweb]

Summary of Bug

if you query /keys and there are no keys yet, the LCD returns "[]" instead of the expected []

Steps to Reproduce

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For Admin Use

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• Appropriate labels applied
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[jackzampolin]

Is this issue anywhere else? I.E. do we frequently return "[]" when there is an empty array?

[alexanderbez]

It should be [] (even in other places where it's not)

[NodeGuy]

Removing the following code fixes the bug:

cosmos-sdk/client/keys/list.go

Lines 51 to 55 in c577831

	// an empty list will be JSONized as null, but we want to keep the empty list
	if len(infos) == 0 {
	PostProcessResponse(w, cdc, "[]", indent)
	return
	}